Missing You by Harlan Cobin

Kat is a cop in NYC. She hasn't gotten over losing her father the cop to murder or her fiance to mysterious circumstances. She can't stand her partner and is drinking too much. Then two things happen. Her friend Stacy signs her up with a dating website and a teenage boy named Brandon comes to her for help in finding his missing mom. And soon Kat realizes Brandon's mom may not be the only one missing...and her ex-fiance may be involved.

Missing You is a gripping, albeit very dark, thriller. I feel like I really need some lighthearted chick lit now
to get some of those dark images out of my head.